1. Field of the Invention
This invention relates to a power supply device, more particularly to a power supply device with a power switching module in the form of a separate PCB (printed circuit board) that is able to be welded to or plugged removably into a primary circuit board such that the power switching module forms a non-zero angle with the primary circuit board.
2. Description of the Related Art
In a conventional power supply device, there are two power switching elements (e.g. MOSFETs) provided in a synchronous rectifier circuit of a secondary-side circuit of a transformer. Such power switching elements will generate a significant amount of heat during operation. As shown in FIG. 1, the general solution to dissipate the heat is to fasten the power switching elements 11, 12 on two opposite surfaces of a heat dissipating element 15 by a screw 13 and a nut (not shown), in which the screw 13 passes through an exposed metal portion 14 of each of the power switching elements 11, 12, thereby dissipating the heat generated by the power switching elements 11, 12 through the heat dissipating element 15. However, this solution requires that a piece of insulator 16 be placed between the heat dissipating element 15 and each of the power switching elements 11, 12, and that an insulator 17 smeared with a heat-dissipating paste be placed between the exposed metal portion 14 of each of the power switching elements 11, 12 and the respective screw 13 or nut so as to prevent the exposed metal portion 14 from being shorted with the heat dissipating element 15, making the procedure complicated, labor-consuming and costly.